Javascript 使用Javascript获取webView内容的总高度

Get total height of webView's content using Javascript

提问by Emil

I'm using a UIWebViewfor displaying content, in the form of an HTML string – not a website, higher than the screen of the iPhone, without needing to scroll in the webView itself, leaving that to the parent scrollView.

我使用 aUIWebView以 HTML 字符串的形式显示内容 - 不是网站，高于 iPhone 的屏幕，无需在 webView 本身中滚动，将其留给父 scrollView。

To achieve this, I need a way to get the total document size, including the scrollable area, to set the webView's height. I have tried a number of different Javascript solutions:

为了实现这一点，我需要一种方法来获取总文档大小，包括可滚动区域，以设置 webView 的高度。我尝试了许多不同的 Javascript 解决方案：

(document.height !== undefined) ? document.height : document.body.offsetHeight // Returns height of UIWebView
document.body.offsetHeight // Returns zero
document.body.clientHeight // Returns zero
document.documentElement.clientHeight // Returns height of UIWebView
window.innerHeight // Returns height of UIWebView -2
document.body.scrollHeight // Returns zero

Is there a solution that actually works?

有没有实际可行的解决方案？

Current (nonworking) code:

当前（非工作）代码：

[[[self.singlePost.contentText subviews] lastObject] setScrollEnabled:NO];
int content_height = [[self.singlePost.contentText stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue];
NSLog(@"Content_height: %d", content_height);
CGRect rect = self.singlePost.contentText.frame;
rect.size.height = content_height;
self.singlePost.contentText.frame = rect;

回答by Andres Kievsky

There is no need to use Javascript in iOS 5.0 and up - you have direct, documented access to its scrollView:

在 iOS 5.0 及更高版本中无需使用 Javascript - 您可以直接、记录在案的访问其滚动视图：

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    CGFloat contentHeight = webView.scrollView.contentSize.height;
    // ....
}

To get the total height of the contents of the webView.

获取 webView 内容的总高度。

回答by karim

When I tried with my code, I found,

当我尝试使用我的代码时，我发现，

(1) NSLog(@"webView height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]);
(2) NSLog(@"webView height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.height"]);

(1)return the height less than the original height. But (2)return the actual height. My suggestion is to get the Maxof the two.

(1)返回小于原始高度的高度。但(2)返回实际高度。我的建议是得到Max两者中的。

- (void)webViewDidFinishLoad:(UIWebView *)theWebView {
    NSLog(@"Body height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]);
    NSLog(@"Doc height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.height"]);
    NSString * javaScript = [NSString stringWithFormat:@"document.getElementById('%@').clientHeight", kDivID];
    NSLog(@"Div height: %@",[webView stringByEvaluatingJavaScriptFromString:javaScript]);
    [self reLayout];
}

- (CGFloat) getWebViewPageHeight {
    CGFloat height1 = [[webView stringByEvaluatingJavaScriptFromString: @"document.height"] floatValue];
    CGFloat height2 = [[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] floatValue]; 
    return MAX(height1, height2);   
}

Output

输出

Body height: 485
Doc height: 509
Div height: 485

回答by robert

Where do you call your code? For me it returns 0 if it is called right after the loadHTMLString Method. If I call it in the (void)webViewDidFinishLoad:(UIWebView *)theWebView delegate, I get a valid value.

你在哪里调用你的代码？对我来说，如果在 loadHTMLString 方法之后立即调用它，它会返回 0。如果我在 (void)webViewDidFinishLoad:(UIWebView *)theWebView 委托中调用它，我会得到一个有效值。

- (void)loadHTML: (NSString *)html {
    webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    webView.delegate = self;

    NSURL *resourceURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]];
    [webView loadHTMLString:html baseURL: resourceURL];
    NSLog(@"height: %d", [[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue]); // returns 0
  }

- (void)webViewDidFinishLoad:(UIWebView *)theWebView {
    NSLog(@"height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]); //return 2166
}

回答by t9mike

I went with a slightly different approach, to create a <DIV> that I could key off of to get the size, because I was having no luck with inspecting document/body.

我采用了一种稍微不同的方法，创建了一个 <DIV>，我可以关闭它以获得大小，因为我在检查文档/正文时没有运气。

This is MonoTouch C#, but should work fine in Objective-C:

这是 MonoTouch C#，但在 Objective-C 中应该可以正常工作：

private const string DIV_ID = "_uiwebview_";

LoadHtmlString("<body style='background-color:#yourcolor; padding:0px; margin:0px'>" +
  "<div style='width:" + Frame.Width + "px; padding:0px; margin:0px; font-family:" + 
  font.Name + "' id=" + DIV_ID + ">" + html + "</div></body>", base_url);

and getting the height in LoadFinished:

并在 LoadFinished 中获取高度：

string sheight = EvaluateJavascript("document.getElementById('" + DIV_ID +
   "').clientHeight");

@Jesse, this works when updating with HTML that would generate a smaller size than was previously shown.

@Jesse，这在使用 HTML 更新时有效，该 HTML 会生成比以前显示的尺寸更小的尺寸。